Have you changed the original speaker for a better one? The stock speaker burns out quickly, and I seem to recall that had some knock on effects on the behaviour of the board?
The next thing to look at would be the throttle settings, I also had to tweak mine to get to an acceptable response - you'll need the programming USB widget to have a fiddle with that tho. Fitting a bigger battery won't help, the El-Mod boards are sometimes too clever for their own good, and use a pre-programmed acceleration curve instead of a linear response to throttle inputs. You need to tweak this to improve the response.
Also I think I had to fiddle with the gear change points as well - seemingly being unable to "get out of first gear" as far as the software was concerned was another problem I can recall
Board works well, once you have spent a few days banging your head against a brick wall fighting it
